One conventional traction control system is of the type in which a throttle valve of a carburentur is operated by a stepping motor or the like, and the stepping motor is controlled by an electronic control device. Another conventional traction control system is of the type in which the injection of the fuel is controlled.
With respect to the conventional traction control system utilizing a stepping motor, intake valves of the engine and other parts need to be changed, and the control is rather complicated resulting in high costs.